Basically, a passive radiator is a reactionary device as the name suggests. When a driver (such as a subwoofer) is mounted to a sealed speaker box (enclosure), the physical forward/back movement of the speaker affects the internal air pressure of the enclosure.
The 3 landforms created by wave erosion sometimes called coastal  erosion are headlands and bays, cliffs and wave cut platforms and  finally caves, arches, stacks and stumps â¦ . Wave erosion is the  wearing away of land and the removal of beach by wave currents.
1 If the cave is formed in a headland, it may eventually break through to the other side forming an arch. 2  The arch will gradually become bigger until it can no longer support the top of the arch. 3  When the arch collapses, it leaves the headland on one side and a stack (a tall column of rock) on the other. and erosion erosion: Erosion is the process whereby rock or soil is worn away by the action of the wind, waves or water. can create caves, arches, stacks and stumps along a headland. Old Harry Rocks, Swanage, Dorset.